I know, or at least I think, the standard is different, but if that were a pass to Walton, there is 0% chance that any ref in any league at any level would say he had control of the ball. So not control, and not down. But I don't think this is the proper analysis.
The analogy should be a fumble. Assume a tackler punched the ball out Walton's hand. At what point does he still have control and at what point does he not have control. I think the replay guys looked at this and believed his kneee was down, which it obviously was, but they must have thought he did not have control of the ball. Now, he had enough control to toss it to his left, but it's not like it was a pretty pitch. He could not have had enough control to make a good toss. That's the only thing that makes sense. Therefore, not down.